Much like the U.S. Air Force with its mix of stealthy and non-stealthy fighters, the Chinese air force is developing a two-tier fighter fleet. Alongside a handful of radar-evading J-20s, Beijing is acquiring hundreds of more-conventional J-10s.

While observers focus their attention on China's new J-20 stealth fighter, the Chinese air force steadily is improving and building more copies of an only slightly less sophisticated fighter: the J-10.